Scientific American's Top 10 Science Stories of 2013

A carbon threshold breached, commitments to brain science made, mystery neutrinos found and human evolution revised—these and other events highlight the year in science and technology as picked by the editors of Scientific American

So many stories, so few slots. Our picks this year run the gamut from physics to biology to technology. But as a group, climate change wins in terms of having the most stories, followed by space science.

As usual, we had to leave out many exciting developments. To that end, we have decided to take a cue from Spinal Tap and turn it up to 11 with this top 10 list: specifically, a page of honorable mentions.

Moon Shot to the Head: Global Initiatives Target the Brain
Big Science in 2013 embraced not a search for yet another subatomic particle, but a quest to elicit the fundamental workings of mind and brain. Large-scale endeavors worldwide embarked on extended sojourns to decode the signals coursing along the 100 trillion connections that tie together 86 billion neurons of the human brain.

Hacking the 1.36-kilogram organ that resides underneath the skull may take decades, perhaps centuries. Still, one giant leap for neuroscience—or at least one small step—came as the Obama administration announced that its second-term showpiece science project would target the brain.

Earlier this year Pres. Obama announced the Brain Research Through Advancing Innovative Neurotechnologies, or BRAIN, initiative. It intends to develop tools that can provide a recording of thousands or even millions of neurons. The goal: gaining an understanding of how physiology—brain cell activity—translates into mental functions. It would reveal the secret of how your neurons file away for later recall a just-learned phone number or perhaps recognize the bloom of a red rose.

A still-more ambitious undertaking had its formal start the second week in October under the aegis of the European Commission. The Human Brain Project targets a full computer simulation of the body’s master controller within 10 years—incorporating the findings from an array of projects, ranging from analyses of cognition in mice and men to building faster supercomputers. Other brain initiatives in China, Israel and Australia are underway. A remarkable consensus seems to be emerging that the yawning gap between mind and brain cannot be bridged without the sustained enterprise of the best and brightest from every corner of the globe. —Gary Stix

Drone plans are taking shape across numerous industries as the U.S. awaits new guidelines from the Federal Aviation Administration, due in 2015, on the domestic use of unmanned aerial vehicles. In the absence of regulatory language, entrepreneurs and technophiles such as Bezos have dreamed up ambitious plans (too ambitious, perhaps) for drone use, just as others have sounded the alarm about the potential for drones to malfunction catastrophically or even fall prey to hackers. Meanwhile, privacy advocates worry that widespread drone use will infringe on civil liberties that have long been taken for granted. In an April editorialScientific American cautioned that unmanned aerial vehicles “pose an immense threat to privacy” if misused by law enforcement agencies, private eyes or even nosy citizens.

And then, of course, there are the drones that kill. In December a drone strike reportedly targeted a wedding convoy in Yemen, killing more than a dozen people. As the powerful, potentially dangerous technology adapts to more and more civilian uses, Scientific American blogger John Horgan warns, “we must stay informed to make sure that drones are deployed for beneficial rather than insidious ends.”—John Matson

Gene Therapy Achieves Major Success
Have blood cancers met their match? Certainly, the enthusiasm greeting gene-therapy results presented in early December at a hematology conference seemed to indicate so. The new weapon against leukemia, however, is not perfect; still, it marks a significant achievement.

In a study begun in 2010 on adults and children suffering from chronic and acute forms of leukemia, researchers extracted the patients’ T cells—the immune system’s targeted torpedoes against invaders. The researchers then genetically modified the T cells to recognize a protein that only exists on cancerous cells and to rapidly proliferate on meeting them. Injected back into the patients, the engineered cells could then seek out and destroy those cells.

Preliminary analyses suggest that positive responses can occur up to two thirds of the time. In a study of 27 patients with acute leukemia, 24 showed complete remission one month after treatment, although six have since relapsed. In another study of 15 patients, six showed complete remission and another six showed a partial response.

Other scientists at the conference also reported positive results with gene therapy on other conditions, including SCID-X1, or “bubble boy” disease. Treatment restored the immune systems of eight of nine boys.

In addition to the reported successes, none of the studies uncovered serious side effects of gene therapy, which in past clinical trials led to a few deaths—most notably that of Jesse Gelsinger in 1999, which set the field back many years. The latest results suggest that gene therapy has turned an important corner and is on the verge of becoming a viable treatment option for life-threatening conditions. Look for an overview article scheduled for the March 2014 Scientific American. —Philip Yam

The boom in oil and natural gas in the U.S. has an unwanted by-product: contaminated water. The nation's fossil-fuel wells produce at least nine billion liters of the stuff every day, and disposing of all that wastewater has become oil and gas companies’ biggest headache—not least because the most common current disposal method is causing earthquakes.

Such wastewater is typically dumped back down a disposal well and forgotten. But an uptick in earthquakes in normally seismically quiescent parts of the country, such as Oklahoma and Ohio, has turned attention to whether that water is promoting temblors. And studies published this year of the unusually powerful earthquakes near Prague, Okla., show that wastewater disposal is indeed to blame.

This is not a huge surprise. Experiments in Colorado in the 1960s proved that injecting water underground could spawn earthquakes. But even pumping water underground at high pressure—the practice known as hydraulic fracturing, or fracking—can set the ground rumbling. The question is: Now that we know, what, if anything, should be done about it? —David Biello

The First Neutrinos from Outside the Solar System
For the first time this year astronomers caught neutrinos originating in distant galaxies, an advance that heralds the start of a new era in astronomy—the era of seeing with particles, not just light.

Scientists have been studying neutrinos for decades, but almost all of the neutrinos here on Earth come from nearby sources—either our own sun or from high-energy cosmic rays hitting the atmosphere. This year astronomers using the IceCube detector at the South Pole reported the discovery of 28 neutrinos that were so energetic they could not have possibly originated in these local sources. (Researchers named the two most powerful neutrinos “Ernie” and “Bert” after the beloved Sesame Street characters.)

As for what spawned these ultrapowerful neutrinos, speculation abounds—the particles didn’t all arrive in a single spurt and appear to come from random directions on the sky. Once scientists can correlate the location of a neutrino burst to an optical counterpart—possibly coming from an energetic, short-lived object like a supernova—the era of neutrino astrophysics will begin in earnest. —Michael Moyer

The thighbone comes from an important site in northern Spain known as the Sima de los Huesos. Previously researchers had obtained DNA from similarly ancient cave bear remains found at the site, raising hopes that recovering DNA from the fossil humans might be next.

The new sequence furnished some startling insights into the ancestry of the Sima people. Based on the anatomy of the fossils, experts suspected they belonged to either early Neandertals or a species called Homo heidelbergensis that is thought to have given rise to Neandertals.

But the DNA they recovered (so-called mitochondrial DNA, which comes from the cell’s energy-producing structures and constitutes only a small portion of an individual’s DNA) resembles that of a mysterious human group known as the Denisovans, who lived in Siberia around 80,000 years ago.

Exactly how the Sima people came to have a Denisovan-like DNA sequence and not a Neandertal-like one is unknown. The recovery of DNA from the cell nucleus, which is far rarer than mitochondrial DNA, would no doubt clarify matters. The sequencing of nuclear DNA from a 700,000-year-old horse fossil in June hints that such a feat may well lie within the realm of possibility. —Kate Wong

On November 8, 2013, Typhoon Haiyan slammed into the Philippines with sustained winds of 305 to 314 kilometers per hour—making it the strongest storm on record to hit land. Three prior storms, the earliest in 1958, had higher winds when out at sea but had weakened before making landfall. Haiyan is now blamed for more than 6,000 deaths and for destroying or damaging homes of more than six million people.

High wind speeds mean great potential damage, because the power in wind increases as the cube of speed; wind that is twice as fast delivers eight times as much power. Jeff Masters, director of meteorology at Weather Underground, estimates that if Haiyan had hit Miami or New York City it could have caused $500 billion in losses.

The storm put climate change back on the front page. Global warming is raising ocean temperatures and putting more moisture into the atmosphere, and scientists think both of those factors can strengthen storms. Research since 2007 indicates that hurricanes, typhoons and cyclones—all just different names for the same type of system—may be getting stronger in the North Atlantic. And recent research by Kerry Emanuel at the Massachusetts Institute of Technology indicates that more storms might form, too, in many of the world’s tropical ocean regions.

Haiyan also motivated Yeb Sano, head of the Philippines’ delegation to the United Nations Framework Convention on Climate Change, to take a personal stand against the lack of progress in international climate talks. At the convention’s meeting that began in Warsaw, Poland, just three days after the typhoon wiped out Sano’s hometown, he announced that he would go on a hunger strike until negotiators made “meaningful progress.” After two weeks he broke his fast, satisfied that negotiators had agreed on provisions that would address damage from future climate change events.—Mark Fischetti

Meteor Explodes over Chelyabinsk, Russia
The world received a blaring reminder that Earth is at risk from asteroids when a large rock from space exploded over the Russian city of Chelyabinsk on February 15. The meteor flew in at almost 60 times the speed of sound, and its breakup in the atmosphere packed as much energy as 500 kilotons of TNT, later analysis showed. The meteor's shock wave shook the ground, shattered glass and injured about 1,500 people; thankfully, no one was killed. Scientists estimate the asteroid started out about 20 meters wide, making it the largest known meteor to strike Earth since an asteroid hit Tunguska, Siberia, in 1908.

The Chelyabinsk fireball came as a surprise, even to those at NASA and the rest of the world's space agencies, which had not spotted the asteroid in advance. And it struck just 16 hours before another, larger asteroid, 2012 DA14, made a close flyby of Earth, passing within the orbital range of geosynchronous communications satellites.

The events were a wake-up call to some about the dangers asteroids pose. In October the United Nations took steps to address the risk by setting up an “International Asteroid Warning Group” for member nations to share detections of hazardous space rocks. If scientists discover an asteroid with Earth's name on it, the U.N.’s Committee on the Peaceful Uses of Outer Space plans to spearhead an international mission to deflect the rock from its course. —Clara Moskowitz

Atmospheric CO2 Reaches a Historical High: 400 Parts per Million
In May concentrations of carbon dioxide in the atmosphere reached 400 parts per million. In other words, human activity, such as fossil-fuel burning and cutting down forests, has boosted greenhouse gas levels to concentrations not seen in at least 800,000 years—or well before human civilization and even modern humans existed.

In fact, the last time CO2 levels are known to have been this high was in the Pliocene epoch more than 2.5 million years ago, when the Arctic boasted forests instead of tundra and the world's average temperature was roughly 3 degrees Celsius warmer. The CO2 in the atmosphere has already boosted average temperatures by 0.8 degree C since the 19th century, and more warming is in store.

More CO2 is in the offing as well. At the present pace, the world could reach 450 ppm in a few decades, ratcheting up concentrations by two ppm or more per year. Ideas for what to do about it range from building artificial trees to pull CO2 out of the air to replacing all fossil fuel–fired power plants with nuclear reactors. But it seems safe to say CO2 levels will get higher—and the globe warmer—before long. —David Biello

U.S. Sequestration: A Body Blow to Science
U.S. researchers shuddered on March 1, 2013, when the sweeping federal budget cuts known as the sequester went into effect. Born amid congressional failure to strike a budget deal, sequestration forced the slashing $85 billion in government spending for the remainder of the fiscal year—and with it, a cascade of cuts to research funding.

That $85 billion was just the start: blunt, across-the-board cuts of $1.2 trillion kicked in, spooling out over nine years through 2021. The mandatory pruning injected uncertainty into the future of science research because the federal government holds the purse strings for more than one third of all research and development in the U.S. Not only did sequestration force the government to slash funding for grants, it also delayed or scuttled plans to bring on new hires. Research groups lamented that the litany of cuts will have long-lasting impacts on innovation because scientific advancement is an incremental process that depends on future researchers—and research—in the pipeline. Francis Collins, director of the National Institutes of Health, even grabbed his guitar and literally sang the “Sequester Blues” this past spring.

Research across a broad spectrum felt the heat. The NIH, the country’s largest supporter of basic reach, had to crop its budget by $1.6 billion for the fiscal year. Those funding constraints helped contribute to 640 fewer research project grants compared with the prior year. The National Science Foundation, hit with $283 million in cuts, also doled out about 700 fewer grants this year. Research grants fluctuate naturally each year, but reductions in various agencies were far greater than the norm. Federally supported science at other agencies—including the U.S. Environmental Protection Agency, Department of Energy and NASA—will also likely feel the budget bite, if they haven’t already.

A new congressional deal, unveiled December 10, may staunch some of the funding loss. But the full impact of the cuts so far is shrouded in uncertainty and may have already set back U.S. innovation for years. —Dina Fine Maron

The Chang’e 3 rover makes China the third nation to visit the moon. The achievement shows how space technology is spreading to other nations and to private companies, which continue to show their ability in launches.